1. Field of the Invention
The present invention relates to an endoscope fitted with a sealed housing and an electrically powered and/or controlled system inside the housing, the endoscope including a light guide sealed against the outside and installed in the housing and fitted at one end with electricity/light transducers.
2. Description of Related Art
Endoscopes of this species are standard design today. The light guide typically is in the form of bundles of optic fibers. As a rule the light guide runs from a lateral, proximal input through the endoscope to a distal end of the endoscope. Light radiates from the light guide at the endoscope distal end surface to illuminate the field of view. A light-guide hook-up cable runs from the lateral input of the endoscope to a lamp, which illuminates the proximal end of the hook-up cable. The lamp in this instance constitutes the electricity/light (E/L) transducer.
Medical endoscopes have a sealed housing protecting the internal optical and electrical devices against exposure to liquids and vapors. Protection against vapors is required due to sterility-mandated steam-autoclaving. The sealing problems encountered in this design have been substantially solved as regards the installation of light guides. Illustratively, full sealing can be attained using soldered glass windows.
Electrical systems installed inside the endoscope, for instance video cameras, stepping motors for focusing etc., however must be powered electrically, that is, being fed with current. Accordingly, these internal electrical systems require external control lines to control their operation or to transmit signals to the outside, for instance control feedback or, in the case of a video camera, a video signal.
Aside from significantly unsatisfactory solutions such as integrated batteries constituting the power supply, or wireless signal transmission, the state of the art typically resorts to electric lines for power and for signal transmission. In addition to the already substantial sealing problems attending the light guides, additional sealing problems are introduced when using electric lines, connectors and the like. In practice, the sealing problems associated with the electric lines, connectors, etc are more difficult to overcome than those presented by the light guides.
An objective of the present invention is to create an endoscope of the above species which eliminates or reduces the sealing problems present in the prior art.
In the invention, the power supply line is a light guide fitted at one end with an E/L transducer and, at the other end, with a light/electricity (L/E) transducer. Using an electric bulb as the E/L transducer and a power L/E transducer at the other end, namely inside the endoscope housing, the electric systems in said housing is then supplied with power. Using modulated E/L transducers such as modulated electric bulbs at one end of a light guide and an L/E transducer designed: for signaling purposes at the other end, a data transmission path is set up to act as a control line or as a signal transmission line for instance of the video signal. Appropriate electro-optic components are available economically and in appropriate dimensions. Electrical lines with their attendant feed through and sealing problems are avoided. The proven sealing techniques for light guides, for instance employing 100% tight windows, can be used.
Moreover, this technique offers the known advantage of reduced susceptibility to spurious electric radiation, which creates a significant problem in the vicinity of electro-surgical instruments.
The light guide used for transmission purposes may be installed in the endoscope housing separately and with its own feed through or access port. However, according to one features of the present invention, use is made of some of the cross-section of the illumination light guide. This space is already present for illumination and, using the proven sealing technique, may be retained to insert the guide into the endoscope and pass it through the endoscope.
The cross-sectional portion of the illumination light guide used as the light guide may terminate more shortly inside the endoscope for the purpose of being coupled to an L/E transducer. The illumination of the transducer may be carried out by the illuminating light source over the common, proximal cross-section. Advantageously, however, and according to another feature of the present invention, the light guide used for transmission purposes is installed over the full installation length together with the illuminating light guide. However, the light guide used for transmission purposes is apposed to the illuminating light guide and presented as a separate bundle of optic fibers that is accessible separately at both ends.
In further accordance with the present invention, the light guide can branch off the illuminating light guide at one or both ends and may advantageously run as far as the assembly site of the associated transducer.
In accordance with another feature of the present invention, the light source used for illumination in particular may serve as a high-power E/L transducer, that is, to feed current. However, the light source may also be modulated and therefore, optionally in superposition, it may be used for data transmission into the endoscope.
Alternatively, and in further accordance with the present invention, a separate light source may be used as the proximal E/L transducer. Such separate light source is of low power and in the form of an LED. This separate light source therefore serves to transmit signals very rapidly and at minimal power.
In further accordance with the present invention, a reverse signal flow is possible to communicate signals from the endoscope to the outside. Such signals may constitute, for instance, a feedback of control signals and/or transmission of video signals.
Using a plurality of transducer-equipped light guides, complex power supplies, control and data transmissions can be carried out using light guide technology. The light guides furthermore may be used for bi-directional signal transmission, optionally with additional power transmission.